答案1
\inttriple
下面定义的宏可以完成这项工作。
\documentclass{article} % or some other suitable document class
\usepackage{mathtools} % for '\mathclap' macro
\newlength\mylen
\settowidth\mylen{$\displaystyle\int$}
%% define a new macro:
\newcommand\inttriple[3]{\mathop{{\int\limits_{\mathclap{#1}}}
\kern-\mylen
{\int_{#2}^{#3}}}}
\begin{document}
\begin{align*}
x &= \int_{0}^{\infty} \\
&= \inttriple{\gamma}{0}{\infty} \\
&= \inttriple{\text{hello}}{0}{\infty}
\end{align*}
\end{document}